The present invention relates to a stent graft having a hollow cylindrical body with a blood side and a vessel side, wherein the stent graft has a first stent graft portion with a self-expanding stent composed of successive rings of meandering supports in its longitudinal direction, and with a first prosthesis material secured on the rings and connecting these on the vessel side of the hollow cylindrical body.
Stent grafts of this kind are well known in the prior art. These vascular stents, also referred to as intravascular or intraluminal stent grafts, or stents for short, are implanted into blood vessels that have been damaged, for example as a result of diseases or the like, or that have been widened by an aneurysm or have had their lumen occluded, as a consequence of which the function of the vessels is greatly impaired or there is a risk of the vessels rupturing. In the prior art, various implantable stent devices are known which, after they have been implanted, keep blood vessels, for example arteries, open or delimit aneurysms from the blood stream. Such stents generally have a tubular or hollow cylindrical body which is inserted into the vessel and is fixed at the appropriate location in order to keep the lumen of the vessel open.
Thus, the prior art includes stent grafts, for example, which have a wire framework made of a self-expanding material, for example Nitinol, wherein the wire framework can additionally be connected to a tube made of textile or PTFE.
For implantation, the stent or stent graft is radially compressed, such that its cross-sectional surface area can be considerably reduced and it can be easily inserted into the vessel. On account of the resiliency of the metal framework or metal stent, the stent expands back to its original shape and in so doing stretches its jacket surface, which wedges itself internally in the blood vessel.
For implantation, the stents are folded up radially and, with the aid of catheters advanced through the lumen, are then inserted into the blood vessel and placed in the correct position in the vessel. The correct position of the stent can be monitored using X-ray markers, for example. To ensure that the stents remain in the folded-up state during their positioning, they are usually arranged in a sheath or in a sheath-like tube, which presses the stent radially inward and compresses it. This so-called withdrawal tube is pulled back after the stent has been positioned in the vessel, in which process the stent is held axially by an abutment element/slide element, which is also designated as a pusher. The pusher lies in contact with the stent and holds the latter in its axial position, while the withdrawal sleeve also surrounding the pusher is detached from the stent, which is thus able to expand and wedge itself in the blood vessel.
When releasing a self-expanding stent or stent graft, the physician often has to apply a considerable force to the pulling grip of the sleeve tube and to the grip used for positioning the implant and connected to the pusher. Besides the force applied, a further critical point is often that the stent, once released, can no longer be rotated or moved in the vessel in order, if necessary, to position it correctly, since otherwise there is a danger of damaging the vessel.
DE 103 35 948 B3 discloses a stent whose support framework is compressed by a thread that is looped around it. The ends of the thread are diverted from the outside into the support framework and are coupled there.
WO 2011/063972 A1 discloses an insertion system for introducing a medical implant into a vessel of a patient, wherein at least one pulling thread is used with which the diameter of an implant can be changed.
Moreover, US 2007/0100427 A1 describes a device having an intraluminal prosthesis with two thread-like connection elements which enclose the prosthesis in the distal and proximal areas and which can compress the prosthesis by being shortened.
Finally, U.S. Pat. No. 5,776,186 describes an insertion device for stent graft systems that have two Nitinol wire loops which form the framework of the stent graft and via which the stent graft is brought to its expanded shape after the insertion catheter compressing the stent graft has been pulled back.
EP 1 964 532 A2 and EP 1 117 341 B1, for example, disclose an insertion system which permits step-by-step release of a stent/stent graft kept compressed by a sleeve tube. Moreover, in the prior art, so-called pistol grips are known which are intended to allow the physician to gently release a stent graft likewise kept compressed by a sleeve tube.
However, the insertion systems described have the disadvantage that it is impossible or almost impossible with them to position the stent, before it is finally released, i.e. to rotate it and move it, in such a way that it comes to lie correctly. This is critical especially in the case of stents/stent grafts with side branches, since these are of course intended to extend into the branching-off blood vessels after the stent/stent graft has been released.